Up to now, fuel cell batteries with cooling systems are known wherein coolants flow in bipolar plates that are located between the individual fuel cell units of a battery. In addition, newer cooling systems have been disclosed for these batteries that are cooled without bipolar plates or filter press technology in a gas or in a fluid bath (see, e.g. German Letters Patent 44 42 285) and comprise fuel cell units that can be individually handled within the battery.
Sealing problems particularly arise in the battery cooling with bipolar plates because regions lie next to one another in which oxidant and fuel, which must be dependably sealed off from one another, are conducted. Given the fuel cell batteries without bipolar plates, which have only been known for a short time (see, e.g. German Letters Patent 44 42 285), fundamentally only two cooling systems have hitherto been known that both have the coolant flow through the battery in a free stream.
Under certain circumstances, however, the problem of uniform distribution and flow-through of the coolant within the fuel cell battery arises in the concept of fluid cooling because the areas close to inlet and discharge openings of the battery have a more intense flow and are thus more intensively cooled than the other areas of the battery. It can also be disadvantageous that many component parts of the battery enter into communication with the coolant--especially when coolants that are incompatible with the materials of the fuel cells are employed.
The full content of the patent bearing serial number German Letters Patent 44 42 285 is herewith referenced and the entire disclosure thereof is incorporated by reference into the subject matter of the present specification.
There is a need for economical batteries of fuel cells, i.e. batteries constructed without bipolar plates, wherein the cooling system assures an optimally uniform distribution of the coolant within the battery. There is also a need in fuel cell batteries with bipolar plates for a cooling capacity that can be added in when the battery must temporarily yield greater powers.